This invention relates to flexible disk drives of the type designed for use with flexible or floppy disks. More particularly, this invention relates to cleaning diskettes for use in cleaning the transducer or transducers installed in such drives.
Flexible disk drives currently are employed in a wide variety of data processing systems as a mechanism for data storage and retrieval. Such drives are designed for use with flexible or floppy disks comprising a flexible polyester substrate with a recording layer deposited on each side, the compound substrate being rotatably enclosed in a protective jacket or envelope. The jacket is provided with an elongated access aperture on each side in order to afford access to an annular band of each recording layer when the flexible disk assembly is inserted into the disk drive.
Flexible disk drives are generally one of two types: single sided or double sided. A single sided flexible disk drive has a single read/write transducer affixed to a rigid arm and a retractable load pad assembly arranged in spaced alignment from the transducer in such a manner that the load pad presses the flexible disk within the jacket against the magnetic transducer during read and write operations. More specifically, the load pad is located within the disk drive assembly in a position in registration with one of the elongated access apertures in the flexible disk jacket so that the load pad may contact the recording media within the disk during a read or write operation. In order to provide easy insertion and removal of the flexible disk from the disk drive, some type of suitable mechanical retracting apparatus is provided for operating the load pad assembly into and out of pressure contact with the flexible disk recording media. A double sided disk drive employs a pair of read/write transducers, a first transducer located on a rigid arm and a second transducer located in a position similar to that of the load pad assembly of a single sided drive. In a manner similar to that employed for the single sided drive load pad assembly, the second transducer is typically provided with a suitable retracting mechanism to enable the second transducer to be placed in pressure contact with the recording medium through the appropriate access aperture during a read or write operation and to enable the flexible disk to be inserted and removed without interference otherwise.
In both types of flexible disk drive, it is necessary to periodically clean the read/write transducers in order to remove accumulated debris from the transducer surface, which debris builds up over use time. Failure to periodically clean the transducer surface results in deteriorated performance of the transducers, with a resulting loss in accuracy in recording and reproducing the digital information carried by the flexible disk recording surfaces. While the transducer may be cleaned manually, it has been found more convenient to provide a specially designed cleaning disk constructed with the same geometry as an ordinary flexible recording disk, but with an annular cleaning element in place of the normal annular recording element. Although two different types of cleaning disks may be constructed: one for a single sided drive and one for a double sided drive, it is preferable to have a universal cleaning disk suitable for use with either type of drive. Due to the different configurations of single sided drives and double sided drives, the cleaning disk requirements are different for each type of drive. For a single sided drive, the cleaning disk should be designed in order to avoid contact through the access aperture between the load pad assembly and the rotating cleaning material within the disk jacket (in order to avoid degradation of the load pad) while at the same time affording intimate contact between the cleaning disk and the transducer. In a double sided drive, on the other hand, the rotating cleaning material should be accessible to both the fixed transducer and the movable transducer so that each transducer surface is swept by the rotating cleaning disk.
In one type of flexible cleaning disk designed for universal use with both single and double sided drives, one of the jacket access apertures is provided with a removable tab portion formed by stamping perforations into the jacket material. In use with a single sided drive, this type of cleaning disk is inserted into the drive with the tab portion in place so that the load pad bears against the tab portion of the jacket to ideally press the underlying rotating cleaning medium against the fixed transducer; while the tab portion is removed to expose the cleaning medium through the access aperture when used with a double sided drive. While somewhat effective when used in a double sided drive with the tab portion removed, this type of cleaning disk suffers from the disadvantage that the tab portion, being formed from the same material as the disk jacket, is relatively stiff and noncompliant: consequently, the loading force afforded by the load pad assembly is not sufficient to guarantee intimate contact between the cleaning medium and the surface of the oppositely disposed fixed transducer. As a result, the cleaning effect is less than optimal.
In another type of commercially available flexible cleaning disk, a removable polyester tab is placed over one of the jacket access apertures. In use with a single sided drive, the tab is left in place so that the load pad bears against the outer surface of the tab; while when used with a double sided drive, the tab is removed to expose the cleaning medium to the movable transducer. This type of cleaning disk suffers from the disadvantage when used in a single sided drive that the pressure load provided by the load pad is distributed over the entire tab surface, due to the relative thickness of the tab (approximately 0.020 inches): consequently, optimal contact is not achieved between the cleaning medium and the surface of the fixed transducer.